Can I install the Internet Security Suite on a 4th computer since one of them crashed?

I brought the ZoneAlarm Internet Security Suite for 3 computers. I had it on 3 computers but one of the computers crashed. So now I want to install this on my new computer. Is it going to let me put it on a 4th computer since I had to get a new one? If yes, Do I have to do anything certain to make it work or do I just install it? If no, that stinks! lol... Also, the first 3 computers
ran Windows XP but this new one runs Windows Vista. Is that a problem? I have ZoneAlarm Internet Security Suite 2008.